Brief introduction of engineering
Shanghai Yangtze River Tunnel Bridge (Chongming River Crossing Passage)
The project is located in the waters of the south port and the north port of the Yangtze River estuary in the northeast of Shanghai. It is a super-large traffic infrastructure project at the mouth of the Yangtze River in China and an important part of the Shanghai-Chengdu Expressway. The completion of this project will improve the structure and layout of Shanghai's transportation system, accelerate the economic integration of the Yangtze River Delta region, better promote the economic development of the Yangtze River basin and even the whole country, and enhance Shanghai's comprehensive competitiveness in the national economy. The project starts from No.5 ditch in Pudong New Area of Shanghai and reaches Chenjia Town of Chongming County via Changxing Island, with a total length of 25.5 kilometers. The project adopts the scheme of "West Tunnel East Bridge", that is, it passes through the waters of the south port of the Yangtze River estuary in the form of a tunnel, with a length of about 8.95 kilometers; Crossing the waters of the North Port of the Yangtze River Estuary in the form of a bridge, with a length of about 16.65 km. According to the highway standard, this project has six lanes in both directions, the design load is Grade I, and the design speed is 80-100 km/h. ..
The shield diameter of Shanghai Yangtze River Tunnel is also larger than any shield tunnel built or under construction in Shanghai, and it has surpassed the GloeneHart Tunnel in the Netherlands, the largest shield tunnel in the world, reaching15.0m, thus winning the first place in the world. After the tunnel is completed, its pavement will be 40 meters below the surface of the Yangtze River. The river is rough and the wheels are rolling under it. What a spectacular scene.
Shanghai Yangtze River Tunnel Bridge Project is an expressway connecting Shanghai and Chongming, and it is also an important part of the Shanghai-Xi 'an line in the national key highway construction plan. After the completion of the tunnel bridge, it will fundamentally change the inconvenient traffic situation in Chongming Island, and at the same time, it is of great significance to enhance Shanghai's radiation capacity and promote the economic integration development in the Yangtze River Delta.
General introduction
Since its construction, Shanghai Yangtze River Tunnel has attracted the attention of peers in the industry because of its "long, large and deep" characteristics. The long shield tunneling distance is as long as 7.5 kilometers at a time, which is unique in the world; Large-the diameter of two super-large shields 15.43 meters, the highest in the world; The river bottom is deep and high water pressure construction, and the deepest covering soil can reach 55 meters. Now, in less than five years, all the world problems have been solved. The power to solve problems, create speed and turn risks comes from independent innovation. Supported by the National 863 Plan and the "Mountaineering Plan" of Shanghai Science and Technology Commission, Shanghai Yangtze River Tunnel has challenged some frontier topics in the field of tunnel engineering, applied for 28 patents and 8 software copyrights, and compiled 14 construction guides and methods. At present, the crystallization of these courage and wisdom has taken root and blossomed in large-scale river-crossing projects such as Shanghai Changjiang West Road Tunnel, Simon Road Tunnel and Hangzhou Qianjiang Tunnel.
Internal introduction
The tunnel starts from No.5 ditch in Pudong New Area and falls to the southwest of Changxing Island via Nangang waters, with a total length of 8.95 kilometers, including 7.5 kilometers crossing the waters. The overall section of the tunnel is designed as a double-tube tunnel, with a clear distance of about16m between two single tubes, and a transverse pedestrian communication channel is set at intervals of about 800m along its longitudinal direction. The outer diameter of the single pipe is φ 1500 cm and the inner diameter is 1370 cm. There are three (3×3.75 m) lanes in the tunnel, that is, two-way six lanes, with a design speed of 80 km/h, an open-cut rectangular buried pipe section in the tunnel, and a working well with a depth of 22×48 m and a depth of about 25 m on the Pudong side and Changxing Island side. Two mud-water balance inflatable shield machines with a diameter of φ 1543 cm were driven from the working well at Pudong side to the working well at Changxing Island side at one time, and the tunnel was connected. The tunnel project * * * uses 8 19 100 cubic meters of concrete and 0/4 tons of steel bars1522/kloc-0.
Brief introduction of engineering
Shanghai Yangtze River Tunnel is located in the northeast of Shanghai, connecting the land area of Shanghai and Changxing Island, and is an important part of the Yangtze River Tunnel and Bridge Project. The person in charge of the on-site project department of Tunnel Co., Ltd. told the reporter that the tunnel with a length of about 8.9 kilometers is the biggest challenge in Shanghai tunnel construction. Through long-term scientific demonstration, under the guidance of the national "863" project "Research on Key Technologies of Super-large and Super-long River-crossing Shield Tunnels", a series of major scientific research projects have been carried out, making the one-time non-stop excavation distance of two super-large shields reach 7.5 kilometers and the maximum buried depth will reach 55 meters, which is unique in the world.
According to the design, the whole tunnel is used as a communication channel in the river for the safe transfer of personnel and work contact. In the 7.5-kilometer-long tunnel, there is a connecting passage every 800 meters, with a total of 8 * * *. At present, three tunnels have been built to closely connect the two tunnels, with a distance of 15 meters. At present, the Yangtze River tunnel is still driven by shield, and the new technology of excavating the connecting passage ensures that the descending tunnel will be completed before the end of the year, laying a solid foundation for the full opening of the tunnel section of the Shanghai Yangtze River Tunnel Bridge project in 2009.
The Yangtze River Tunnel and the Yangtze River Tunnel Bridge Project were opened to traffic on June 365438+1October 365438+1October 2009.
engineering
precise
The error of "walking" 7.5 kilometers at a time is less than 2.7 cm.
It is hard to imagine that at the bottom of the Yangtze River with extremely complicated hydrogeological conditions, the five-story "Big Mac" shield machine is under tremendous water pressure and even "walked" 7.5 kilometers at a time. What is even more incredible is that the elevation error of the whole tunnel after completion is less than 2 cm, and the horizontal error is less than 2.7 cm. How is such an accurate underwater crossing achieved?
Researchers installed a large number of sensors on two shield machines in advance and corrected them while walking. Under the strict supervision of the three-dimensional axis control system, the walking route of "Big Mac" is almost straight. Professor Li Yongsheng, deputy head of the National 863 Project "Research on Key Technologies of Super-large and Super-long Cross-river Shield Tunnels" and executive vice president of Tongji University, told the reporter that before, the domestic shield tunneling distance was generally about 2 kilometers. It has also been demonstrated several times whether the 7.5 km shield of the Yangtze River Tunnel is "stopped all the way" or "stopped halfway". Considering that the exposed area of this construction is large, the soil layer is extremely unstable, and the settlement is greater when it stops, and the resistance is greater, it is finally decided to do it in one go.
The "dragon" at the bottom of the river with a diameter of 15 meter can be called a monster, but the process of prefabricating and assembling the "dragon body" is more delicate than embroidery. According to reports, the whole tunnel consists of more than 4,000 concrete rings with a width of 2 meters, and each ring tunnel is assembled by 10 wedge-shaped segments. In order to ensure that each ring can be spliced into a perfect circle, the size and shape of 10 segment are not exactly the same, and the width should be controlled between 1.98m and 2.02m, and the manufacturing error must be less than 0.5mm. ..
complicated
"Three floors" and "five rooms" keep cars and subways abreast. Liu Qianwei, deputy general manager of Shanghai Yangtze River Tunnel and Bridge Construction and Development Co., Ltd., showed a tunnel profile to the reporter. The circular tunnel with an inner diameter of 13.7 meters is cleverly divided into "three floors" and "five rooms" (five different functional areas): the upper floor is a ventilation passage for fire fighting and smoke exhaust; Three 5.2-meter-high expressways in the middle layer are spacious and bright; The lower floor is divided into three parts, with track space reserved for the planned subway 19 line in the middle, evacuation passage on the left and cable passage on the right.
Such a well-designed structure was appraised as "the most effective form of space utilization" by the industry, which saved the resources of digging another rail transit tunnel and saved the construction cost by about 654.38+0 billion yuan.
In the process of tunnel construction, similar "haggle over every ounce" can be seen everywhere. For example, each step of two slurry balance shield machines needs a certain amount of supporting slurry, and at the same time, the cutter head at the head of the shield machine will dig out a lot of complicated river bottom sludge. Can you "dilute" the thick slurry dug in the previous meter into the thin slurry in the next meter? The construction workers meditated around the mud pile. Finally, the research group developed a set of high-efficiency and environmentally-friendly mud water treatment system with independent intellectual property rights, which successfully solved the problem of ultrafine particle separation in clay stratum and made the recovery rate of shield mud water exceed 80%.
safe
"8 horizontal and 26 vertical" escape system scientifically guides evacuation
There seems to be not enough space in the tunnel, but enough escape space is reserved in case of emergency. Between the ascending tunnel and the descending tunnel, there is a horizontal escape passage with a length of 15m and a width of 1.8m every 830m, and there are eight escape passages in the whole journey. Between the highway layer and the rail intersection layer of each tunnel, there is an evacuation staircase with 26 exits every 260 meters, and all exits are marked with brackets.
Such a "8 horizontal and 26 vertical" three-dimensional escape system is really rare in the existing tunnel layout. Once an accident occurs in the tunnel, the intelligent evacuation sign at 50 meters will automatically tell the driver and passengers whether to run left or right through the arrow, and reach the escape exit as soon as possible. In the event of a fire, the three smoke exhaust points before and after the ignition point will automatically open, and smoke will be inhaled quickly, so as to minimize the danger of passengers being poisoned and suffocated.
Considering the safety and comfort, the design of the 8.95km tunnel is people-oriented. In the few seconds when entering and leaving the tunnel, the driver always feels uncomfortable because of the flashing lights. At this time, several high-pressure sodium lamps with light close to sunlight can alleviate similar "black hole" and "white hole" effects; In the tunnel, the brightness of LED light source can be adjusted according to the change of external light. In order to relieve visual fatigue, the waistline color of the tunnel is divided into two parts: the first half is blue and the second half is green. It is estimated that various humanized designs can reduce the traffic accident rate of the Yangtze River Tunnel by 20%-30%.
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